A fatal error has occured during the attempt to resize the "https://electrisize.de/wp-content/uploads/2017/08/MG_0197a-2.jpg" image.
Possible causes and their solutions (in the order of occurence) are:
/wp-content/uploads/freshizer/
directory does not exist on your webserver.
array(4) { ["type"]=> int(1) ["message"]=> string(80) "Allowed memory size of 268435456 bytes exhausted (tried to allocate 24576 bytes)" ["file"]=> string(128) "/is/htdocs/wp1137653_G42Q983E20/html/www/electrisize/wp-content/plugins/fresh-framework/framework/extern/freshizer/freshizer.php" ["line"]=> int(1831) }